This question helps understand why the conductivity readings change as the water source moves from near the beach to further up the river. Conductivity and salinity are related to the concentration of total dissolved solids (TDS). How well water conducts electricity (conductivity) is directly related to the concentration of dissolved salt. Pure distilled water should have a conductivity reading of 0 because there are no dissolved solids. Seawater typically has a conductivity reading of 56,000 µS/cm.
We are using the conductivity reading (in micro Siemens per cm) versus the distance from the beach to see if the conductivity reading follows a trend in relation to distance to the beach. We would expect that as the distance from the beach increases the salt content in the river would decrease. However, the numbers for the conductivity seen in the data table vary greatly. In order to account for this we have decided to average the measurements and make a scatter plot of the conductivity vs. the distance from the beach.
Graph:
What Does This Mean???
By analyzing the above graph our initial prediction was proven to be incorrect. We had expected that the salt content would be greatest in the parts of the river that are closest to the beach and would taper off farther away from the ocean. The above scatter plot represents the conductivity of the water with respect to the distance from the beach that the water sample was taken. At a distance of 0 (at narragansett beach) the conductivity is not a maximum. The salt content at Sprague bridge is actually greater than that at narragansett beach. Aside from this data point there is a general trend in the data showing that the conductivity decreases as distance from the beach increases (as expected). The sources of error throughout this experiment that may have thrown off our data could be related to the experimental apparatus. The conductivity probe had several different settings and if it was not calibrated properly the resulting measurements could be inaccurate. Many of the measurements did not match up with the theoretical numbers that would be expected. For example, salt water generally has conductivity of 56,000 µS/cm and our measurements were orders of magnitude off of this number.
Narrow River Investigation: What Did We Find Out
Objective: Each group should use our shared Narrow River Data Set to teach us something interesting.
assign roles in your group: 2 people should analyze data, 1 person should do background research and 1 person should write the conclusion.
use a graph as evidence for your claims.
Question:
Conductivity vs. Salinity -- how are conductivity and salinity related, and how does it change with the distance from the beach.Group Members:
Missy, Chris P, DaveBackground Research
http://cimic.rutgers.edu/~project/epa/Glossary.htm
http://www.mbhes.com/conductivity_measurement.htm
Why is this question interesting?
This question helps understand why the conductivity readings change as the water source moves from near the beach to further up the river. Conductivity and salinity are related to the concentration of total dissolved solids (TDS). How well water conducts electricity (conductivity) is directly related to the concentration of dissolved salt. Pure distilled water should have a conductivity reading of 0 because there are no dissolved solids. Seawater typically has a conductivity reading of 56,000 µS/cm.How are you using our data? (access our data table here)
We are using the conductivity reading (in micro Siemens per cm) versus the distance from the beach to see if the conductivity reading follows a trend in relation to distance to the beach. We would expect that as the distance from the beach increases the salt content in the river would decrease. However, the numbers for the conductivity seen in the data table vary greatly. In order to account for this we have decided to average the measurements and make a scatter plot of the conductivity vs. the distance from the beach.Graph:
What Does This Mean???
By analyzing the above graph our initial prediction was proven to be incorrect. We had expected that the salt content would be greatest in the parts of the river that are closest to the beach and would taper off farther away from the ocean. The above scatter plot represents the conductivity of the water with respect to the distance from the beach that the water sample was taken. At a distance of 0 (at narragansett beach) the conductivity is not a maximum. The salt content at Sprague bridge is actually greater than that at narragansett beach. Aside from this data point there is a general trend in the data showing that the conductivity decreases as distance from the beach increases (as expected). The sources of error throughout this experiment that may have thrown off our data could be related to the experimental apparatus. The conductivity probe had several different settings and if it was not calibrated properly the resulting measurements could be inaccurate. Many of the measurements did not match up with the theoretical numbers that would be expected. For example, salt water generally has conductivity of 56,000 µS/cm and our measurements were orders of magnitude off of this number.